The excitation of elastic oscillations in solid-state gravitational wave antennas by cosmic rays

The problem of nonthermal noise caused by the thermoelastic excitation of acoustic oscillations by incident secondary cosmic ray particles in a solid-state gravitational wave detector is considered. The thermoelastic force arising as a consequence of the nonuniform heating of a solid by the absorption of energy from incident particles (primarily nuclear fragments) and the amplitudes of the waves thus generated are analysed and the coincidence rate of cosmic-ray-generated impulses in two gravitational wave detectors is calculated. It is found that cosmic ray effects are only perceptible in a Weber-type antenna during intense cosmic ray showers, while the more sensitive monocrystalline sapphire detectors require constant protective measures, such as enclosure in lead or concrete chambers, to limit the registration of cosmic-ray-induced signals.